U.S. patent number 8,088,072 [Application Number 12/245,567] was granted by the patent office on 2012-01-03 for methods and systems for controlled deployment of needles in tissue.
This patent grant is currently assigned to Gynesonics, Inc.. Invention is credited to Jordan Bajor, Malcolm G. Munro, Michael Munrow.
United States Patent |
8,088,072 |
Munrow , et al. |
January 3, 2012 |
Methods and systems for controlled deployment of needles in
tissue
Abstract
Needles are deployed in tissue under direct ultrasonic or other
imaging. To aid in deploying the needle, a visual needle guide is
projected on to the image prior to needle deployment. Once the
needle guide is properly aligned, the needle can be deployed. After
needle deployment, a safety boundary and treatment region are
projected on to the screen. After confirming that the safety
boundary and treatment regions are sufficient, the patient can be
treated using the needle.
Inventors: |
Munrow; Michael (Belmont,
CA), Bajor; Jordan (Palo Alto, CA), Munro; Malcolm G.
(Tarzana, CA) |
Assignee: |
Gynesonics, Inc. (Redwood City,
CA)
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Family
ID: |
40534934 |
Appl.
No.: |
12/245,567 |
Filed: |
October 3, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090099544 A1 |
Apr 16, 2009 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60979613 |
Oct 12, 2007 |
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Current U.S.
Class: |
600/464; 600/424;
600/439; 600/462; 600/463; 600/427 |
Current CPC
Class: |
A61B
90/36 (20160201); A61B 18/1477 (20130101); A61B
10/0045 (20130101); A61B 34/10 (20160201); A61M
5/46 (20130101); A61B 2090/378 (20160201); A61B
2010/045 (20130101); A61B 2018/1425 (20130101); A61B
90/11 (20160201); A61B 2034/107 (20160201) |
Current International
Class: |
A61B
8/14 (20060101) |
Field of
Search: |
;600/439 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO |
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WO 98/11834 |
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WO |
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WO |
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WO 99/43366 |
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WO |
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WO 00/00098 |
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WO |
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WO 01/80723 |
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Nov 2001 |
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WO |
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WO 01/95819 |
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WO |
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WO 02/11639 |
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Feb 2002 |
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WO |
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WO |
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WO 03/005882 |
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WO |
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WO |
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WO |
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WO |
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WO |
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WO |
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WO 2004/064658 |
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Aug 2004 |
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WO |
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Other References
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(51): 1707-1716. cited by other .
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Tumors," 11:30 a.m. CST, Monday, Nov. 27, 2000. cited by other
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Senoh et al., "Saline Infusion Contrast Intrauterine Sonographic
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of Uterine Fibroids. cited by other .
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inventor: Michael A. Munrow. cited by other.
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Primary Examiner: Jung; Unsu
Assistant Examiner: Impink; Bradley
Attorney, Agent or Firm: Wilson Sonsini Goodrich &
Rosati
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of prior provisional
application No. 60/979,613, filed on Oct. 12, 2007, the full
disclosure of which is incorporated herein by reference.
Claims
What is claimed is:
1. A method for deploying at least one needle in tissue, said
method comprising: positioning a probe having a deployable needle
proximate a surface of the tissue; providing a real time image of
the tissue including an anatomical feature to be treated;
overlaying the real time image with a projected treatment region
based on the position of the probe; repositioning the probe to
align the projected treatment region on the real time image so that
the treatment region includes at least a portion of the anatomical
feature to be treated; and deploying the needle from the probe
after the probe has been repositioned; wherein the probe is
positioned in a uterus and the anatomical feature to be treated
includes a fibroid.
2. A method as in claim 1, further comprising: overlaying the image
of the tissue with a projected position of the needle; overlaying
the image of the tissue with a projected safety boundary based on
the projected position of the needle; and visually confirming that
sensitive anatomic structures are outside of the safety
boundary.
3. A method as in claim 2, wherein visually confirming comprises
confirming that the needle is no closer than 0.5 cm to the
sensitive anatomic structures.
4. A method as in claim 3, wherein the sensitive anatomic structure
to be maintained outside of the safety boundary includes a
serosa.
5. A method as in claim 2, further comprising enabling a treatment
device if the sensitive anatomic structures are outside of the
safety boundary.
6. A method as in claim 5, wherein enabling comprises responding to
a prompt from the treatment device asking if the sensitive anatomic
structures are outside of the safety boundary.
7. A method as in claim 2, further comprising: marking a location
of the needle after the needle has been deployed; and updating the
projected treatment region and the projected safety boundary based
on the marked location of the needle.
8. A method as in claim 1, further comprising marking a location on
an image of the needle after the needle has been deployed; and
updating the projected treatment region based on the marked
location of the needle.
9. A method as in claim 1, wherein the image is provided by a
transducer on the probe.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to medical methods and
apparatus. More particularly, the present invention relates to
methods and systems for controlling the deployment of needles using
visual feedback from an ultrasonic or other image.
Current medical treatments of organs and tissues within a patient's
body often use a needle or other elongate body for delivery of
energy, therapeutic agents or the like. Optionally the methods use
ultrasound imaging to observe and identify a treatment target and
the position of the needle relative to the treatment target.
Of particular interest to the present invention, a treatment for
uterine fibroids has recently been proposed which relies on the
transvaginal positioning of a treatment device in the patient's
uterus. A radiofrequency or other energy or therapeutic delivery
needle is deployed from the device into the fibroid, and energy
and/or therapeutic substances are delivered in order to ablate or
treat the fibroid. To facilitate locating the fibroids and
positioning the needles within the fibroids, the device includes an
on-board ultrasonic imaging array with a field of view in a
generally lateral direction from an axial shaft. A curved needle is
advanced from the shaft and into the field of view so that the
needle can be visualized and directed into the tissue and the
targeted fibroid. The geometry of the needle deployment is
advantageous since it permits the location and treatment of
fibroids which are laterally adjacent to the shaft.
While effective and very beneficial for patients, such needle
ablation and treatment protocols face several challenges. First,
initial deployment of the needle can be difficult, particularly for
physicians who have less experience. While the physician can view
the tissue and target anatomy in real time on an imaging screen, it
can be difficult to precisely predict the path the needle will take
and assess its final treatment position. While the needle can
certainly be partially or fully retracted and redeployed, it would
be advantageous to minimize the number of deployments required
before treatment is effected.
A second challenge comes after the needle has been deployed. While
the position of the needle can be observed on the ultrasonic or
other visual image, the treatment volume resulting from energy or
other therapeutic delivery can be difficult to predict. As with
initial positioning, experience will help but the need to exercise
judgment and conjecture is best reduced.
A third challenge is in assuring that nearby sensitive tissue
structures, such as the serosa surrounding the myometrium, are not
unintentionally damaged. As with judging the treatment volume,
predicting the safety margin of the treatment can be difficult.
For these reasons, it would be desirable to provide improved
systems and methods for the deployment of energy delivery and other
needles within ultrasonic or other imaging fields of view in energy
delivery or other therapeutic protocols. It would be particularly
useful to provide the treating physician with information which
would assist in initial deployment of a needle in order to improve
the likelihood that the needle will be properly positioned relative
to a targeted anatomy to be treated. It would also be desirable,
once the needle has been deployed, to provide feedback to the
physician to assist in accurately predicting a treatment volume.
Such information should allow the physician, if necessary, to
reposition the needle in order to increase the likelihood of fully
treating the anatomy. Furthermore, it would be desirable to provide
feedback to the physician allowing the physician to assess a safety
margin so that sensitive tissue structures are not damaged. All
such feedback or other information are preferably provided visually
on the ultrasonic or other imaging screen so that the needle
position can be quickly predicted, assessed, and treatment
initiated. At least some of these objectives will be met by the
inventions described hereinafter.
2. Description of the Background Art.
U.S. Patent Publication No. 2006/0189972, published on Aug. 24,
2006 and commonly assigned with the present application, describes
probes useful for both imaging and treating uterine fibroids, which
probes could be used in the systems and methods of the present
application. Other commonly assigned applications describing probes
useful for treating uterine fibroids in the systems and methods of
the present invention include application Ser. No. 11/409,496,
filed on Apr. 20, 2006; Ser. No. 11/564,164, filed on Nov. 28,
2006; Ser. No. 11/620,594, filed on Jan. 5, 2007; and provisional
application No. 60/938,140, filed on May 15, 2007, the full
disclosures of which are incorporated herein by reference. Other
related, commonly assigned applications are Ser. No. 11/620,569,
filed Jan. 5, 2007; and Ser. No. 11/775,452, filed on Jul. 10,
2007. The full disclosures of each of these commonly owned, pending
applications are incorporated herein by reference.
BRIEF SUMMARY OF THE INVENTION
The present invention provides both methods and systems for
deploying one or more needles in tissue. The needles are usually
intended to deliver a therapy to the tissue, most typically being
adapted to deliver radiofrequency, plasma, heat, or other energy to
ablate or otherwise modify the tissue or a targeted anatomy within
the tissue. In other embodiments of the present invention, however,
particularly those relating to initial needle deployment, the
needles could also be intended for biopsy or have other diagnostic
purposes.
One or more needles are deployed in tissue where the tissue is
being imaged so that at least a portion of the needle (once
deployed) and at least one anatomical feature within the tissue
will be visible, preferably on a display screen in real time
before, after, and/or during needle deployment. In a first specific
aspect of the present invention, the image is overlaid with
projected needle treatment information. By "projected," it is meant
that the needle treatment information is predicted or calculated
based on known or determined system information. For example, the
shape of the needle and mechanics of the needle deployment system
may be used to predict the path that the needle may take into
tissue, as described in greater detail below. The treatment volume
and safety boundaries or margins may be calculated or predicted
based on the energy delivery characteristics of the system together
with the anticipated tissue characteristics. The information
overlaid on the image will allow a user, typically a treating
physician, to evaluate the predicted and/or actual needle positions
relative to both treatment efficacy and safety.
In the exemplary embodiments, at least one needle will be deployed
from a probe where the probe may be introduced to the uterus or
other body cavity or lumen. Exemplary anatomical features that may
be imaged and subsequently treated or biopsied include fibroids,
tumors, encapsulated tissue masses, pseudoencapsulated tissue
masses, and the like. Of particular interest to the present
invention, the probe may be positioned in the uterus and the needle
deployed to a location proximate or into a fibroid located in the
myometrium surrounding the uterus. In such cases, it will usually
be desirable to also image the serosa which surrounds the
myometrium and/or other sensitive anatomical features that could be
damaged by the energy-mediated or other therapeutic treatment.
Thus, in a first specific aspect of the present invention, the
projected needle information will include at least a projected
safety boundary which provides a visual image of the treatment
volume that can be provided through the needle. In such cases,
evaluating can comprise confirming that the serosa or other
sensitive tissue or anatomical structure is outside of the
projected safety boundary (where tissue within the projected safety
boundary is at risk of tissue damage). The projected safety
boundary will usually provide a minimum distance between the needle
and the serosa or other sensitive anatomical feature which is at
least 0.5 cm, often being at least 0.7 cm, and preferably being at
least 1 cm.
In a second specific aspect of the present invention, the projected
needle treatment information will comprise a projected needle
deployment path. The projected needle deployment path will
typically find use prior to needle deployment where the treating
physician can manipulate the probe which carries the needle so that
the projected needle treatment path visible on the display screen
is aligned so that the needle will enter or at least be reasonably
close to the targeted anatomy to be treated. The projected needle
treatment information will be based on the known mechanical
characteristics of the needle and may vary for different needles.
In some instances, it will be desirable to actually test individual
needles which are being used so that their individual
characteristics are known, but this will usually not be necessary.
It will be appreciated that the actual needle entry path, while
predictable within certain tolerances, may differ from the
projected path due to differences in the tissue characteristics,
small differences in the deployment mechanisms, differences in the
needle characteristics, or other reasons. In such instances, the
methods and systems of the present invention will allow for
inputting the actual treatment position so that the safety and
treatment boundaries can be predicted based on the actual needle
position, not the predicted needle position. For example, the
physician may locate a known point or artifact on the needle which
appears in the visual image. By then "clicking on" that point or
otherwise feeding that positional information back into the imaging
and control system, the system can recalculate the actual needle
position and, based on the actual position, calculate the safety
and treatment boundaries.
In a third specific aspect of the present invention, the projected
needle treatment information comprises a projected therapy region.
The projected therapy region will be a boundary or volume which is
shown on the visual display to allow the treating physician to
assess whether the target region to be treated will likely be
effectively treated based on the needle position. As just
discussed, usually the projected needle treatment information is
preferably based on the actual needle position but could also be
based on the projected needle position. Thus, it may be possible
for the treating physician to rely on a projected therapy region
(as well as a projected safety boundary) while the projected needle
position is being manipulated relative to the targeted anatomy to
be treated. After actual deployment, the system can recalculate
both the projected therapy region and the projected safety boundary
to allow the treating physician to confirm both that the treatment
will likely be effective and that the serosa and/or other sensitive
tissue structures will not be damaged.
In a further specific aspect of the present invention, the
treatment system will provide for an interlock or enablement step
before treatment can be delivered to the tissue. For example, the
system may require the treating physician to acknowledge that
either or both of the safety boundary and treatment volumes have
been observed and evaluated to determine that the treatment will be
safe and/or effective. Without such acknowledgement, the system
could preclude energy delivery until such time as the treating
physician acknowledges evaluation of the safety and/or
effectiveness. In other instances, the system could be modified to
assess the projected boundaries relative to the targeted treatment
anatomies and the sensitive tissue anatomy, although such fully
automated systems are not presently preferred.
The methods of the present invention will preferably employ the
uterine fibroid treatment probes, such as those described in the
commonly owned, copending applications incorporated herein by
reference above. These treatment probes comprise a shaft having
both an imaging transducer and a deployable needle near the distal
end. The needle is configured so that it may be selectively
advanced in a generally lateral direction within the field of image
of the transducer, typically an ultrasonic imaging array. After the
needle has been advanced into the tissue, and the safety and
effectiveness of the needle position have been confirmed, therapy
may be administered through the needle, such as radiofrequency
tissue treatment or other energy or non-energy mediated treatments.
Exemplary energy treatment modalities include radiofrequency,
microwave, high intensity focused ultrasound (HIFU), liquid
infusion, plasma infusion, vapor, cryotherapy, and the like.
In another embodiment of the present invention, a needle is
deployed in tissue by first positioning a probe having a deployable
needle proximate a surface of the tissue. An image of the tissue is
provided in real time, and a projected needle path is overlaid on
the image. Prior to actually deploying the needle, the probe is
repositioned to align the projected needle path on the real time
image with anatomical feature. After the probe has been
repositioned to optimize the position of the projected needle path
within the anatomical feature, the needle may be deployed from the
probe. After the needle has been actually deployed, the actual
needle position may be fed back into the imaging system by marking
a location on an image of the needle. Based on the actual needle
position provided by the marked location, the projected safety
boundary may be calculated by the system and overlaid on the image.
Based on the projected safety boundary, the physician may visually
confirm that sensitive anatomic structures are safe. Usually, the
tissue image will also be overlaid with a projected treatment
boundary based on the marked location. The physician may then also
visually confirm that at least a portion of the anatomical feature
to be treated is within the projected treatment boundary. The
system may also be programmed so that the treatment device will be
enabled only if the sensitive anatomic structures are outside of
the safety boundary, typically by requiring the treating physician
to acknowledge that the anatomical structures are safe.
Systems for deploying needles in tissue in accordance with the
principles of the present invention comprise a probe and a system
controller. The probe includes one or more deployable needles and
an imaging transducer, where the needle(s) is (are) configured to
be advanced into an image field produced by the imaging transducer.
The system controller includes a screen for displaying the image
produced by the transducer, where the system controller provides
for an overlay on the screen with projected needle treatment
information. The projected needle treatment information may
comprise a projected needle path, where the physician can
manipulate the probe to align the projected needle path with a
target anatomy in the image field visible on the screen. The needle
information may further comprise a projected treatment boundary
and/or projected safety boundary. In such instances, the system may
require the physician to confirm that the projected or actual
needle position is safe and/or effective prior to enabling a
therapy. Usually, the system will be able to update the projected
needle information based on the actual needle position. In
exemplary systems, the system controller further includes a
generator for producing a therapy to be delivered through the
needle, such as a radiofrequency, microwave, high intensity focused
ultrasound (HIFU), vapor, liquid infusion, and cryotherapy. Systems
may employ needle arrays comprising multiple needles.
Methods for treating fibroids and other anatomical features further
comprise deploying at least one needle in the uterus proximate,
usually within, the anatomical feature. The methods may deploy
multiple needles in needle arrays. Radiofrequency energy is
delivered into the feature through an exposed portion or portions
of the needle, where no exposed needle portion is closer than 0.5
cm to the serosa, usually being no closer than 0.7 cm, and
preferably being no closer than 1 cm. such methods can achieve
effecting treatment of many or most fibroids or other features
without damaging the serosa.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of the system comprising a
system controller and a needle treatment probe constructed in
accordance with the principles of the present invention.
FIGS. 2 through 4 illustrate an exemplary needle treatment probe
which may be used in the methods and systems of the present
invention for the treatment of uterine fibroids.
FIG. 5 is a flowchart illustrating an exemplary treatment protocol
in accordance with the principles of the present invention.
FIGS. 6A and 6B illustrate use of the needle treatment probe of
FIGS. 2 through 4 in the treatment of a uterine fibroid in
accordance with the principles of the present invention.
FIG. 7 illustrates exemplary dimensions for a treatment region and
a safety boundary for the needle deployment probe of FIGS. 2
through 4.
FIGS. 8A through 8G illustrate exemplary images which might be
viewed by a treating physician when deploying the needle deployment
probe of FIGS. 2 through 4 in treating a uterine fibroid generally
as shown in FIGS. 6A and 6B.
DETAILED DESCRIPTION OF THE INVENTION
As illustrated in FIG. 1, a system 10 constructed in accordance
with the principles of the present invention includes both a system
controller 12 and treatment probe 14. The system controller 12 will
include a processing and power unit 16 and a display screen 18. The
controller 12 will further include means for the treating physician
to input information, such as a keyboard, touch screen, control
panel, or the like. The processing and power unit 16 will usually
include a radiofrequency, microwave, vapor, treatment plasma, or
other circuitry or mechanisms for delivering the treatment energy
or other treatment agents to the treatment probe 14. Conveniently,
the system controller 12 could comprise a conventional desktop or
laptop computer to provide both the screen and logic and be
connected to a separate radiofrequency, microwave, HIFU, liquid
infusion, plasma infusion, vapor, cryotherapy or other source to
provide the desired treatment.
The treatment probe 14 typically includes a shaft 20 having a
handle 22 at its proximal end. A needle 24 and imaging array 26 are
provided at the distal end of the shaft 20, as described in more
detail with reference to FIGS. 2 through 4. The treatment probe 14
shown in FIGS. 2 through 4 is described in more detail in copending
provisional application No. 60/938,140, filed on May 15, 2007, the
full disclosure of which has previously been incorporated herein by
reference.
The probe 14 generally includes a rigid or other delivery shaft 20,
an ultrasound imaging transducer 26, and an echogenic curved needle
24 with an artifact/feature 100 at a distal end 51 (FIG. 3)
thereof. As shown, the artifact is a corner cut type
retroreflector. The handle 22 is attached to a proximal end 21 of
the shaft 20. A distal end 23 of the shaft 20 has a bent or
deflectable distal tip, as best seen in FIG. 4. The ultrasound
imaging transducer 26 comprises a linear ultrasound array disposed
in a flat viewing window 36 (FIG. 3) which images in a field of
view 46 (FIG. 4). Although only a single straight needle 24 is
illustrated, the probe may carry multiple needles in arrays and/or
the needles may be straight or have any other configuration.
The needle 24 is a solid tip electrically conductive needle
intended for radiofrequency tissue ablation. As discussed
elsewhere, it could also be intended for delivery of other forms of
energy or be a hollow core needle intended for substance delivery
or injection. The exemplary needle 24 generally comprises a
two-piece construction including an elongate hollow body 48 (as
best seen in FIG. 3) and a solid distal tip 50 at a distal end
thereof The distal tip 50 may be laser welded to the hollow tubular
body 48 . The solid tip 50 may also be attached via alternative
means, for example adhesives or mechanical features or fits. The
hollow tube 48 will generally have a length in a range from about
20 cm to about 45 cm. In some embodiments, the hollow tube will
have an oval cross section having a thickness generally in a range
from about 0.5 mm to about 2 mm and a wideness generally in a range
from about 1 mm to about 3mm. This flattened oval cross sectional
shape, when present, is intended to inhibit lateral deflection
during deployment or penetration of the needle 24 . FIG. 3 also
illustrates a representative laser cut hole 60 within the distal
end of the tubular body 48 for the infusion of agents (e.g.,
electrolytes, drugs, etc.) so as to enhance the therapeutic effect
of the needle 24 prior to or during ablation treatment. The
infusion hole 60 may be aligned on one side of the tubular body 48
and generally has length in a range from about 0.5 mm to about 2 mm
and a width in a range from about 0.5 mm to about 2 mm. It should
be noted that hole 60 may comprise one or a plurality of holes, and
each may be used for a different purpose.
The handle 22 further includes a longitudinally movable slider 72
for enabling the advancement and retraction of the needle 24 to and
from within a needle guide 44. The ultrasound imaging transducer 26
may optionally be present on an imaging insert replaceably disposed
within the axial passage of the shaft 20 . A sealing element 30 may
be provided between the ultrasound imaging transducer 26 and the
shaft handle 22 to ensure sufficient sealing around the insert at a
proximal end. It will be appreciated that the above depictions are
for illustrative purposes only and do not necessarily reflect the
actual shape, size, or dimensions of the system 10 . Furthermore,
the ultrasound imaging transducer may comprise an ultrasound array
which may be parallel to an axis of the shaft 20 or may be slightly
inclined as illustrated in FIG. 4. This applies to all depictions
hereinafter. The array is typically a linear array with from 16 to
128 elements, usually having 64 elements. The length (azimuth) of
array usually ranges from about 5 mm to about 20 mm, normally being
about 14 mm. The array may have a depth (elevation) ranging from
about 1 mm to about 8 mm, normally being about 2 mm. In an
embodiment, the ultrasound array transmits ultrasound waves at a
center frequency ranging from about 2 MHz to about 15 MHz,
typically from about 5 MHz to about 12 MHz, normally about 6.5
MHz.
Referring now to FIG. 5, an exemplary protocol for performing the
needle positioning methods of the present invention for treating
uterine fibroids will be described. After the probe 14 is
positioned in the uterus, the treating physician scans the
myometrium M in order to locate fibroids F, as shown in FIG. 6A.
Shaft 20 is manipulated so that the field of view 46 of the
transducer array 26 provides a visual image, such as that shown in
FIG. 8A, on the screen 18 of the system 10. Once a fibroid F is
located, the physician can scan the image for other anatomical
features such as the treatment-sensitive serosa S, as also shown in
FIG. 8 A. It should be appreciated that the image being produced is
"real time," and that the image will change as the physician moves
the shaft 20 within the uterus U so that the field of view 46 scans
over different portions of the myometrium.
The next step in the protocol of FIG. 5 relies on aligning a needle
guide overlay with the fibroid. The needle guide may be a simple
pair of parallel lines 70, as shown in FIG. 8B. The parallel lines
70 will typically represent the limits of the most likely lateral
needle advancement path. Thus, by aligning the lines 70 generally
across the target fibroid F, as shown in FIG. 8C, the likelihood
that the needle will be directed into the middle of the fibroid is
increased.
The treating physician continues to visually assess the position of
the needle guidelines 70 relative to the fibroid F until they are
acceptably aligned, as shown in FIG. 8C. The physician then
advances the actual needle into the tissue as shown in FIG. 6B,
where the image of the actual needle is shown in FIG. 8D. After the
image of the actual position of the needle appears, the physician
marks a preselected position on the needle, either by moving a
cursor on the image and clicking, touching the screen, or the like.
Such "marking" of the actual position allows the system to
calculate or recalculate a projected safety boundary and a
projected therapy region. For example, the system may be marked
near the tip of the needle, as shown at location 80 on FIG. 8E.
Referring now to FIG. 7, an exemplary safety boundary 90 and
treatment region 92 for a single needle fibroid ablation system
will be described. A treatment needle 24 has an uninsulated
treatment portion 96 having a length l in the range from 1 cm to 3
cm, typically being 2 cm. The safety boundary will be an oval line
which is generally a distance s from the exposed exterior of the
treating electrode portion 96. The distance s is usually in the
range from 1 cm to 3 cm, typically being about 1.5 cm. A distance t
between the exposed needle portion 96 and the treatment region
boundary 92 will typically be about half that of the safety
distance s, typically being in the range from 0.5 cm to 1.5 cm,
usually being about 0.75 cm. Generally, the distance tt from the
distal tip of the needle 24 and the safety boundary and the
treatment region perimeter will be somewhat less because of the
reduced energy density at the tip. Thus, the distance tt between
the tip and the treatment region perimeter may be from 0.1 cm to
0.5 cm, usually being about 0.25 cm while the distance ts between
the tip and the safety boundary will be in the range from 0.5 cm to
1.5 cm, typically being about 1 cm.
Based on these desired clearance distances, the system projects
treatment and safety overlays on the actual image of the needle 24,
as shown in FIG. 8F. The physician can then visually assess whether
sensitive tissue structures, such as the serosa S remain outside of
the projected safety boundary 90. As shown in FIG. 8F, the serosa S
is inside of the safety boundary 90, so it will be necessary to
reposition or redeploy the needle 24 to move the serosa S beyond
the safety boundary. It is noted that the position of the treatment
perimeter 92 about the fibroid F is probably sufficient for
treatment, but the needle needs to be deployed based on safety
concerns.
Once the needle has been repositioned or redeployed so that the
treatment region 92 sufficiently covers the fibroid F while the
safety boundary does not encroach upon the serosa S as shown in
FIG. 8G, the physician will enable the system for treatment.
Usually, the system will require the physician to acknowledge that
the needle has been properly positioned before allowing the system
to power the needle. Once that is done, the physician can initiate
treatment, as described generally in the prior applications which
have been incorporated herein by reference.
While the above is a complete description of the preferred
embodiments of the invention, various alternatives, modifications,
and equivalents may be used. Therefore, the above description
should not be taken as limiting the scope of the invention which is
defined by the appended claims.
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